JP2004012200A - X-ray tomograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray tomograph for adjusting a location of an object to be tested in the direction other than rotational and vertical directions of a rotation table while X rays are radiated, identifying an observed region of the tested object, picking up a projected image of the object to be tested as a position after a location adjustment is maintained and having a micromotion means for not influencing concentricity of an air bearing if the air bearing is used for a rotation base. <P>SOLUTION: The X-ray tomograph is provided with the rotation base for mounting the object to be tested 7 between an X-ray source and a two-dimensional detection means for picking up the projected image of the tested object and having a rotational axis perpendicular to a normal from an X-ray focus to a light receiving face of the two-dimensional detection means; a vertical direction micromotion mechanism for adjusting a location of the rotation base in the vertical direction. The micromotion means 9 has a horizontal direction micromotion location adjustment mechanism for adjusting a location of the rotation base on a surface perpendicular to the rotational axis. While the rotation base rotates and the projected image of the object to be tested 7 is picked up, a drive source 13 of the micromotion means 9 is wholly isolated from the rotation base. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an X-ray tomographic imaging apparatus that inspects an internal structure of an object using X-rays.
[0002]
[Prior art]
2. Description of the Related Art In the field of research and development of semiconductor devices and the like, nondestructive three-dimensional analysis is required to inspect cracks, disconnections, and the like existing inside a minute test object. As a method used as one of the methods, there is a tomographic imaging method using X-rays. An X-ray tomographic imaging apparatus (X-ray CT apparatus) includes, for example, an X-ray source (an X-ray generating apparatus including an X-ray tube or the like) and a cone beam from the X-ray source to an object to be inspected through an X-ray focal point. A two-dimensional detecting means for detecting X-rays which are radiated and transmitted in a shape, and an object to be inspected is placed between the two-dimensional detecting means and lowered from the X-ray focal point to a light receiving surface of the two-dimensional detecting means. There is a microfocus X-ray CT apparatus having a rotation base orthogonal to a perpendicular and having a rotation base rotating at an angular displacement pitch based on a setting. The transmission X-rays of the object to be inspected are imaged by the two-dimensional detection means, processed as a plurality of digitized image data (projection data) for each angular phase, etc., and the internal structure data is reconstructed from each of the image data. Inspection and observation of the inside of the object to be inspected are performed.
[0003]
For example, in a microfocus X-ray CT apparatus that rotates an object to be inspected between an X-ray source and a two-dimensional detector, two-dimensional detection means having a capability of detecting a projected image having a size of about A4 is used. A region of the test object which can be reconstructed with an enlarged view field of about 150 times by rotating a minute test object having a size of, for example, 15 × 15 mm and a thickness of about 1 mm placed on a rotary table of the base and irradiating with X-rays. Is about 1 mm 2 near the rotation axis of the internal space of the test object. Usually, it is necessary to search for this part while magnifying and seeing it before acquiring projection data for reconstruction.
[0004]
[Problems to be solved by the invention]
Conventionally, a mechanism that vertically adjusts the position of the entire inspection object rotating mechanism that grips and rotates the inspection object has been used, but fine movement on a plane orthogonal to the rotation axis mounted on the inspection object rotating table has been used. There was no table. Therefore, when the inspection object is rotated by a single scan method using cone-beam-shaped X-rays to acquire projection data from all circumferential directions, when the specific region is located at an end of the inspection object, In order to prevent the projected image from protruding out of the field of view of the two-dimensional detection means, the distance between the object to be inspected and the X-ray focal point has to be increased at the expense of magnification. Further, even if the projected image enters the field of view of the two-dimensional detection means, there is a disadvantage that the reconstructed image is deteriorated because the specific portion is not near the rotation axis of the test object.
[0005]
In the above case, when it is determined that the specific part of the test object is located at a deviated position inside the test object, the X-ray irradiation is stopped and the ionizing radiation shielding window of the shield cover is opened, as shown in FIG. If the mutual position of the inspection object gripping mechanism and the inspection object is manually adjusted, the specific portion can be moved to the vicinity of the inspection object rotation axis. This task of making very small position adjustments is time consuming.
[0006]
Further, as shown in FIG. 8, when a plurality of portions having a high X-ray absorption coefficient are arranged inside the object to be inspected, an X-ray is not transmitted through the portion which overlaps on the irradiated X-ray, and the portion is accurate. No projection data can be obtained. If the specific part is stepped in the thickness direction of the flat object to be inspected and if it is possible to tilt or flip the flat plate, such as when you want to extract a part of it and enlarge it, see through the part where projection data should be acquired. It becomes easy to specify while doing. Further, if the projection data is acquired with the tilted or raised posture, it can be deleted from the data to be stored as the upper and lower end faces of the projected image before the reconstruction calculation, and the quality of the reconstructed image can be improved.
[0007]
In addition, when the air bearing is selected and used as a rotation bearing of the rotation base portion that supports the entire rotation base portion mechanism and can smoothly rotate and control minute angular displacement, the rotating portion of the air bearing is actually used. Is floating on a thin air film, and the rotating shaft is eccentric in proportion to the radial load of the rotating shaft. Therefore, the use of a mechanism for generating a radial load on the rotary table of the air bearing must be avoided. In order to permit the rotation of 360 ° or more, wiring connected to the outside should not be provided on the rotary table, but fine movement means of a mechanism satisfying such a required function has not been proposed.
[0008]
In view of the above, the present invention adjusts the position of the test object in a direction other than the rotation direction and the vertical direction of the turntable while continuing the X-ray irradiation, specifies a portion of the test object to be observed, and It is possible to capture a projection image of the test object while maintaining the adjusted posture, and has fine movement means that does not affect the concentratority of the air bearing when an air bearing is used for the rotating base. It is an object to propose an X-ray tomographic imaging apparatus.
[0009]
[Means for Solving the Problems]
According to the present invention, an object to be inspected is placed between an X-ray source and a two-dimensional detecting means for capturing a projected image of the object to be inspected, and a perpendicular line dropped from an X-ray focal point to a light receiving surface of the two-dimensional detecting means is formed. In an X-ray tomographic imaging apparatus having a rotation base having orthogonal rotation axes and a vertical fine movement mechanism for adjusting the position of the rotation base in the vertical direction, the object to be inspected is moved in a direction other than the rotation direction of the rotation axis and the vertical direction. A fine movement means having a fine movement mechanism capable of adjusting the position in the direction of is provided, and is configured as follows.
[0010]
The X-ray source tomographic imaging apparatus of the present invention places an object to be inspected between an X-ray source and a two-dimensional detecting means for imaging a projected image of the object to be inspected, and detects the two-dimensional detecting means from the X-ray focal point. In an X-ray tomographic imaging apparatus having a rotation base having a rotation axis orthogonal to a perpendicular line dropped on a light receiving surface and a vertical fine movement mechanism for adjusting the position of the rotation base in a vertical direction, A first fine movement means having a horizontal fine movement position adjusting mechanism for adjusting the position on a plane orthogonal to the rotation axis.
[0011]
According to the present invention, the object to be inspected can be finely moved in a plane perpendicular to the rotation axis of the rotating base while the X-ray irradiation is continued, and the specific portion inside the object to be inspected is projected image thereof. Can be adjusted to be located near the rotation axis.
[0012]
Further, the X-ray tomographic imaging apparatus of the present invention mounts an object to be inspected between an X-ray source and a two-dimensional detecting means for imaging a projection image of the object to be inspected, and detects the two-dimensional detecting means from an X-ray focal point. In a X-ray tomographic imaging apparatus having a rotation base having a rotation axis perpendicular to a perpendicular line dropped on the light receiving surface, and a vertical fine movement mechanism for adjusting the position of the rotation base in the vertical direction, A second fine movement means composed of a gonio stage having an orthogonal turning center axis is provided.
[0013]
According to the present invention, while the X-ray irradiation is continued, the object to be inspected is finely turned around a turning center axis orthogonal to the rotation axis of the rotating base, so that a plurality of the objects can be inserted inside the object to be inspected. Even when parts having high X-ray absorption coefficients are arranged on a straight line, the heights of these parts can be individually separated in the vertical direction to specify a part to be observed of the object to be inspected.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of an X-ray tomographic imaging apparatus according to the present invention will be described with reference to FIGS.
[0015]
In this example, a tomographic imaging apparatus using X-rays will be described. However, the present invention is not limited to X-rays, and other types of radiation or the like may be applied to an object from multiple directions to obtain a plurality of images. Any device may be used as long as it uses a method of reconstructing and calculating internal structure data from the projection image of.
[0016]
FIGS. 1A and 1B are schematic views of an example of an X-ray tomographic imaging apparatus used for industrial use, for example, for nondestructive inspection for inspecting the internal structure of a minute inspection object such as a semiconductor element. In the figure, reference numeral 1 denotes a known X-ray source (X-ray generation device) that generates, for example, cone-beam X-rays and irradiates the entire inspection object 7, and is irradiated from the X-ray tube 1 of the X-ray generation device. An X-ray image of a projection image of the inspection object 7 is taken by the X-ray, and the transmitted X-rays of the inspection object 7 at this time are converted into an X-ray two-dimensional detector (hereinafter also referred to as a two-dimensional detector) as two-dimensional detection means. 2) Capture in step 2 to obtain a projected image.
The X-rays emitted from the X-ray tube 1 are configured to form an extremely small X-ray focus having a focus size of 5 μm or less, for example. The resolution of the X-ray tomographic imaging apparatus is determined mainly by the focal size of the X-ray, and the smaller the numerical value is, the more preferable it is to observe damage of a smaller size.
[0017]
The X-ray two-dimensional detector 2 is composed of, for example, a flat panel detector (FPD), and can adjust the movement in the left, right, up, and down directions so that transmitted X-rays are emitted to the center. The FPD is specifically disclosed in JP-A-6-342098. X-rays transmitted through a subject are absorbed by a photoconductive layer such as an a-Se layer to generate electric charges corresponding to the X-ray intensity, and the amount of the electric charges is detected for each pixel. As an example of another type of FPD, as disclosed in JP-A-9-90048, X-rays are absorbed by a phosphor layer such as an intensifying screen to generate fluorescence, and the intensity of the fluorescence is detected. There is something. As another means for detecting the fluorescence, there is a method using a CCD or a C-MOS sensor.
[0018]
In particular, in the FPD of the method disclosed in the above-mentioned JP-A-6-342098, since the X-ray dose is directly converted into the charge amount for each pixel, sharpness deterioration in the FPD is small and an image excellent in sharpness is obtained. . As described above, the present invention is not limited as long as an image signal can be obtained by capturing X-rays such as X-rays and processing each pixel by some means.
[0019]
Reference numeral 3 denotes an entire rotating base (hereinafter referred to as a rotating base) including a rotating base on which the test object 7 is mounted, a motor for rotating the rotating base, a bearing described later, and the like. The rotation base 3 includes a Z-axis drive mechanism 3a that moves in a direction parallel to the rotation axis of the rotation base 3, that is, as shown in FIG. 1A, in the Z-axis direction (vertical direction). The test object 7 is held and fixed by a holding jig 8 on a rotating base.
[0020]
In this example, the rotating base 3 is supported by an air bearing, which will be described later, and the rotating axis is orthogonal to a vertical line dropped from the focal point of the X-ray tube 1 to the X-ray two-dimensional detector 2. This air bearing supports the rotating base 3 and can rotate smoothly to control the minute angular displacement. The servo motor, which is directly coaxially connected to the air bearing and has an angular positioning accuracy of 0.2 minutes or less, and a rotary motor. The phase detecting means stops at each angular displacement corresponding to the resolution of the servo motor and the rotational phase detecting means in synchronization with the above-mentioned projection data fetching period required for reconstruction.
[0021]
Reference numeral 5 denotes an XY table on which the X-ray tube 1 of the X-ray source is mounted and which moves on a plane orthogonal to the rotation axis of the bearing 4. The turning radius of the test object 7 is fed back to the XY table 5 as needed, and projection data can be acquired in a state where the test object 7 and the X-ray focus are brought extremely close as needed. The highest-order element that governs the magnification is the distance between the X-ray focal point and the inspection object 7 held on the rotating base 3. If the magnification is large, the internal structure of a finer part is analyzed. It is possible to do.
[0022]
Reference numeral 6 denotes an entire horizontal fine movement position adjustment mechanism (horizontal fine movement mechanism) described later, on which a test object 7 and a holding jig 8 as a means for holding and fixing the test object 7 are mounted. The holding jig 8 is fixed to a horizontal fine movement table 9 that finely moves on a plane (horizontal direction of the X-ray tomographic imaging apparatus) perpendicular to a rotation axis of the bearing 4 described later.
[0023]
Reference numeral 40 denotes an anti-vibration table that mounts all the devices and members constituting the above-described X-ray tomographic imaging apparatus and removes vibrations so as to prevent errors in the irradiation position. Reference numeral 41 denotes a shield cover made of lead or the like that covers the whole so that X-rays such as X-rays do not leak to the outside from the X-ray tomographic imaging apparatus.
[0024]
FIG. 2 is a configuration diagram of the X-ray tomographic imaging apparatus of this example.
First, X-rays are emitted from the X-ray tube 1 constituting the X-ray source to the inspection object 7 mounted on the rotating base 3. The test object 7 is finely adjusted in position by the rotating base 3, the Z-axis drive mechanism 3a and the horizontal fine movement mechanism 6, and is set to the most appropriate position for observing a desired part. At this time, the intensity of the irradiated X-rays, the focus size, and the like are controlled by a control console 32 as a control operation means through an X-ray control unit 30 as an X-ray control means.
[0025]
The position, rotation angle pitch, initial rotation angle, and the like of the rotation base 3 are controlled by a control console 32 through a mechanism control unit 31 that is a mechanism control unit that controls the movement of the rotation base 3 and the XY stage 5. . The test object 7 placed on the rotating base 3 is rotated by an angle specified by the control console 32, and the projected image is captured by the X-ray two-dimensional detector 2.
[0026]
The control console 32 is provided with input means such as a keyboard, for example, comprises a personal computer or the like, and has information processing means for processing information and display means for displaying input values and the like. For example, information such as the X-ray intensity from the X-ray tube 1 is taken into the control console 32 and displayed on this display means, and the position of the object 7 to be inspected relative to the rotating base 3 and the horizontal fine movement mechanism 6 is adjusted. A command for output can be output.
[0027]
The X-rays transmitted through the test object 7 are captured and detected by the X-ray two-dimensional detector 2 such as an FPD. The X-ray two-dimensional detector 2 supplies a projection image, which is information of the detected X-ray, to a projection image storage unit 33 as projection image storage means. The converted projection data is stored in a projection image storage unit 33 composed of a large-capacity magnetic recording medium or the like at an appropriate location according to the angle. The projection image storage means is not limited to a recording medium having a recording capacity capable of recording projection data, and various types such as an optical disk and a semiconductor memory can be applied.
[0028]
The projection data stored in the projection image storage unit 33 is supplied to a reconstruction calculation computer 34 as reconstruction means connected thereto. The projection data stored in the projection image storage unit 33 is stored by the control console 32 in association with information such as the rotation angle pitch, initial rotation angle, and X-ray intensity of the projection image.
[0029]
The reconstruction calculation computer 34 reconstructs and calculates the internal structure data from the input projection data. The reconstructed internal structure data is stored in the projection image storage unit 33 or another recording medium and is not shown. The information is input to the reconfiguration result display device 35 as display means via the display memory, and is displayed on a display such as a CRT monitor. The reconstruction calculation computer 34 has only to have an arithmetic processing capability capable of collecting input projection data and reconstructing internal structure data, and may be shared with the information processing means of the control console 32. The display means such as the reconstruction result display device 35 may be shared with the display means of the control console 32. Further, the display means of the reconstruction result display device 35 may be shared with the display means of the control console 32.
[0030]
As described above, the internal structure data of the inspection object 7 is obtained on the reconstruction result display device 35 and the internal structure is displayed, and defects such as cracks and disconnections inside the inspection object such as minute electronic component elements can be easily obtained. Can be visually confirmed.
[0031]
FIG. 3 is a top view of the entire horizontal fine movement position adjusting mechanism of the X-ray tomographic imaging apparatus according to the present invention, and FIG. 4 is a side view thereof.
[0032]
The horizontal fine movement table 9 shown in FIG. 4 has a fixed member 10 fastened to the bearing 4 and a cross roller (not shown) provided in the horizontal fine movement mechanism in the horizontal direction in the drawing as a linear movement guide. Can be finely moved in a plane (horizontal plane) perpendicular to the rotation axis of the bearing 4 via twelve ball screw drive systems.
[0033]
The motor 13 is a drive source of the ball screw drive system 12, while the rotation of the bearing 4 lowers the cylinder 14 and is separated. When the inspection object is to be inspected at the rotation origin angle position of the bearing 4, when the projection data inside the inspection object 7 is specified while searching for a part to be acquired in an enlarged field of view, the projection data is moved to the vicinity of the rotation axis of the bearing 4. , The cylinder 14 is raised, the pressure rollers 15 and 16 are connected, and the ball screw 12 is driven to finely move the horizontal fine movement table 9.
[0034]
Reference numeral 17 denotes an entire clamp mechanism (clamp) having a member 18 fastened to the bearing 4 and pressed against both the horizontal fine movement table 9 and the fixed-side member 10 when the bearing 4 rotates. The clamp is controlled to open when the self-holding solenoid 20 is excited.
[0035]
Reference numeral 19 denotes a tension means such as a tension coil spring. The play of the ball screw 12 is canceled by the tension coil spring 19, but immediately after the cylinder 14 is further lowered and the motor 13 is disconnected, the position of the cylinder 14 is detected and projected. Immediately before the data is acquired, the excitation of the self-holding solenoid 20 via the leaf spring energizing section 22 is released, and the member 18 forming the clamp 17 is used for both the horizontal fine movement table 9 and the fixed side member 10 fastened to the bearing 4. Pressed to. As described above, the self-holding solenoid 20 is configured such that the clamp 17 is closed in the non-excited state, and the connection with the external wiring having the leaf spring energizing section 22 as a contact is cut off with the rotation of the rotating base 3. I have.
[0036]
As a result, the function of the tension coil spring 19 is assisted, and the backlash present in the cross roller portion as the linear motion guide is removed. After a series of operations, during the acquisition of the projection data, that is, during the rotation operation starting from the rotation origin position of the bearing 4, the external force in the bearing radial direction removes any wiring even the rigidity of the wiring of the self-holding solenoid 20. You can ignore it.
[0037]
Since the bearing 4 has an air bearing structure, the bearing 4 is in a state of floating on a thin air film, and unnecessary external force undesirably affects the concentricity of the rotating shaft of the bearing 4. Further, the fact that the entire horizontal fine movement position adjusting mechanism 6 does not require wiring is advantageous when performing continuous rotation imaging of 360 ° or more, and a slip ring or the like for releasing the rigidity of the wiring is unnecessary, and the horizontal fine movement position adjustment is unnecessary. The entire mechanism 6 can be simplified.
[0038]
21 is a balancer for the vertical load of the bearing 4. As shown in FIG. 3, the horizontal fine movement position adjusting mechanism 6 provided on the upper part of the bearing 4 is symmetrical in the vertical direction as shown in FIG. 3, but the load can be evenly applied to the horizontal direction in the figure by the balancer 21. Therefore, no external force is applied to the bearing 4 in the radial direction, and there is no unnecessary external force.
[0039]
In particular, when an air bearing is used for the bearing 4 as in this example, it is necessary to focus on the concentricity of the rotating shaft. However, the above configuration can solve this problem. it can.
[0040]
FIG. 6 is a schematic diagram in which a specific portion inside the flat plate-like inspection object is moved by the horizontal fine movement table 9 to the vicinity of the rotation axis of the bearing 4. As shown in FIG. 5, for example, FIG. 5 shows a position adjustment method for identifying and capturing an image at the left end of the flat plate-shaped test object 7 where three high-X-ray absorption coefficients are arranged as a part to be observed. The description will be made according to the flowchart shown.
[0041]
First, the test object 7 is fixed to the holding jig 8 and fastened to the horizontal fine movement table 9 previously moved to a position where the test object 7 and the holding jig 8 do not enter the transparent field of view of the two-dimensional detector 2 (step S1) After performing pre-calibration of the two-dimensional detector 2 so that cone beam-shaped X-rays emitted from the X-ray tube 1 are irradiated to the center of the two-dimensional detector 2 through the inspected object 7 approximately. (Step S2), X-rays are irradiated to the object 7 to be inspected (Step S3).
[0042]
The X-axis direction of the lower XY table 5 of the X-ray tube 1, the self-holding solenoid 20 and the cylinder 14 are appropriately operated so that the entire projection of the object 7 enters the center of the two-dimensional detector 2 (step S4). ). Then, a destructible specific site where a reconstructed image inside the inspected object 7 is to be obtained is searched (step S5).
At this time, even if the X-ray tube 1 is moved in the X-axis direction by the XY table 5, the virtual projection coordinates of the air bearing rotation center axis of the bearing 4 (when the rotation axis is assumed to be projected on the two-dimensional detector 2) Is adjusted so that the perpendicular line dropped from the X-ray tube 1 to the two-dimensional detector 2 in advance and the rotation center axis of the bearing 4 intersect perpendicularly, so that the coordinate position on the two-dimensional detector 2 Does not move.
[0043]
Next, it is checked whether or not there is any influence on the reconstructed image by a part having a high X-ray absorption coefficient near the specific part of the subject 7 (step S6). If there is an influence, the posture of the test object 7 is changed using a gonio stage described later, but in this example, it is assumed that there is no influence and the process proceeds to the next step.
[0044]
In step S6, when there is no influence on the reconstructed image due to a portion having a high X-ray absorption coefficient in the vicinity of the specific portion of the test object 7, it does not interfere with the maximum turning radius of the holding jig 8 when the bearing 4 is turned. The X-ray tube 1 is brought close to just before (step S8).
[0045]
Next, it is checked whether or not the specific part of the inspection object 7 is near the rotation of the bearing 4 (step S9). If not, the X-ray tube 1 approaching the inspection object 7 is again removed. Separate them so as to keep a certain distance (step S10). Then, the self-holding solenoid 20 is excited, the clamp 17 is released, the cylinder 14 is raised, the horizontal fine movement table 9 is driven by the motor 13, and the specific part is moved in the field of view near the rotation axis of the bearing 4. Thereafter, the cylinder 14 is lowered, the excitation of the self-holding solenoid 20 is released, and the member 18 of the clamp 17 is pressed and fixed to both the horizontal fine movement table 9 and the fixed-side member 10 (step S11), and then the step S8 is performed. Returning to the process, the X-ray tube 1 is again brought close to the holding jig 8 for holding the inspection object 7.
[0046]
When the specific part of the test object 7 is near the rotation axis of the bearing 4, it is determined whether or not the specific part is near the height of the perpendicular dropped from the X-ray focal point to the two-dimensional detector 2 with respect to the test object 7. Check (step S12). When the specific part is near the height of the perpendicular, the subject 7 is separated from the X-ray transparent field by the horizontal fine movement table 9, and the irradiated X-ray is located at the center of the imaging area of the two-dimensional detector 2. The calibration of the two-dimensional detector 2 is executed. Thereafter, the horizontal fine movement table 9 is returned to the original coordinates before the separation (step S14).
[0047]
If the specific portion is not near the height of the perpendicular dropped from the X-ray focal point to the two-dimensional detector 2, the Z-axis drive mechanism 3a is driven to adjust the position in the Z-axis (height) direction (step S13). ), The process proceeds to step S14, and similarly, the inspection object 7 is separated from the X-ray transmission field on the horizontal fine movement table 9, and the calibration of the two-dimensional detector 2 is executed. Thereafter, the horizontal fine movement table 9 is returned to the original coordinates before the separation.
[0048]
When the preparation up to this point is completed, the acquisition of the projection data for reconstructing the internal structure data centering on the vicinity of the specific part of the inspected object 7 is started (start S15). Then, the internal structure data of the specific part of the object to be inspected is reconstructed from the acquired projection data to evaluate the object to be inspected.
[0049]
According to such a present example, the horizontal fine movement position adjusting mechanism (horizontal fine movement table 9) on the plane orthogonal to the rotation axis of the bearing 4, which is the inspection object rotation mechanism, is provided. Even when it is at the end of the object 7 to be inspected, the position can be adjusted so that the specific part is near the rotation axis of the bearing 4 while irradiating the X-ray. It is not necessary to sacrifice the magnification so as not to go outside, and it is possible to prevent the image of the reconstructed internal structure data from deteriorating.
Further, it is possible to reduce the time wasted when the position of the specific portion of the test object 7 is adjusted to the vicinity of the rotation axis of the bearing 4 by a conventional manual operation.
[0050]
When an air bearing is used for the bearing 4, the drive source of the horizontal fine movement table 9 is separated from the entire rotation mechanism and the drive source is rotated while the rotation base is rotated and a projection image is captured as in this example. Immediately before disconnection from the entire rotation mechanism of the base unit, the clamp 17 holds the coordinate position of the test object and releases the holding operation by the clamp 17 during the coordinate position adjustment period of the test object 7. An external force in the radial direction with respect to the rotating shaft is discharged, and the concentricity of the rotating shaft of the rotating base can be maintained.
[0051]
Next, another example of the embodiment of the X-ray tomographic imaging apparatus of the present invention will be described.
In this example, similarly to the above-described example, the object to be inspected is placed between the X-ray two-dimensional detector that captures the projected image of the object to be inspected, and the object is lowered from the X-ray focal point to the light receiving surface of the two-dimensional detector. An X-ray tomographic imaging apparatus having a rotary table having a rotation axis orthogonal to a vertical line, comprising a vertical fine movement mechanism for vertically adjusting a position of an entire inspection object rotation mechanism, and an X-ray tube of an X-ray source. A device that captures a projected image of an object to be inspected by X-rays irradiated in a more cone beam shape, and captures a transmitted X-ray of the object to be inspected by an X-ray two-dimensional detector to obtain a projected image. It is.
[0052]
Therefore, in the X-ray tomographic imaging apparatus of this example, instead of the horizontal fine movement table 9 as the horizontal fine movement position adjusting mechanism of the embodiment described above, fine movement orthogonal to the rotation axis of the inspection object rotating mechanism is performed. A gonio stage 25 having a turning center axis is mounted. Alternatively, a gonio stage is additionally provided on the horizontal fine movement table 9. Otherwise, the configuration is the same as that of the above-described example. In FIG. 7, portions corresponding to those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0053]
FIG. 7 shows a schematic diagram in which a gonio stage is installed on the horizontal fine movement table 9 of the X-ray tomographic imaging apparatus. In the figure, reference numeral 25 denotes a gonio stage, which is set on the horizontal fine movement table 9 and can turn around a turning center axis orthogonal to the rotation axis of the bearing 4.
[0054]
In the gonio stage 25, a mechanism in which either the tilt direction or the tilt direction of the test object 7 is manually (manually) adjusted as needed and tightened by a screw or the like (not shown) may be used. As in the case of the horizontal fine movement table 9 of the adjusting mechanism, the driving force may be transmitted from outside the bearing 4 via the pressure rollers 15 and 16. When the driving source is shared with the horizontal fine movement position adjusting mechanism in this manner, for example, a pressure roller similar to the pressure roller 16 is prepared, and the phase of the pressure roller is shifted by 90 ° with respect to the rotation axis of the bearing 4. Mechanical interference can be prevented.
[0055]
The basic fine movement position adjustment method of the specific part of the test object on the gonio stage 25 is the same as the horizontal fine movement position adjustment method described above with reference to FIG.
However, as described briefly in step 6, when there is an effect on the reconstructed image due to a portion having a high X-ray absorption coefficient near the specific portion, that is, as shown in FIG. If there is a high part, the X-ray irradiation is stopped, the gonio stage 25 is driven to adjust and change the posture of the inspection object 7 (Step S7), and the process returns to Step S3 to irradiate the X-ray again. Then, the processes after step S4 are performed, and the search for the non-destructive specific portion of the inspection object 7 is advanced.
[0056]
In this example, the holding jig 8 on which the test object 7 is placed by the gonio stage 25 as shown in FIG. By tilting or raising the, it is possible to easily specify the part from which projection data is to be acquired while seeing through.
[0057]
Also, if the object is rotated at the stage where the part is specified and the projection object is rotated with the posture tilted or raised to acquire the projection data, the upper and lower end faces of the projected image can be used before the reconstruction calculation near the specific part. It is possible to delete the data from the data, the reconstruction calculation area indicated by the arrow in the figure can be limited, and the quality of the reconstructed internal structure image can be improved.
[0058]
As shown in FIG. 7, a specific portion inside the flat plate-shaped test object in which a plurality of portions having a high X-ray absorption coefficient are arranged is selectively enlarged, and the holding jig 8 is moved around the rotation axis of the bearing 4. When the turning radius r2 at the time of turning is minimized, the rotation axis of 4 is brought close to the X-ray focal point, and the posture of the inspection object 7 that maximizes the magnification is determined. The interior can be inspected in more detail. The rotation radius r2 of the gonio stage 25 can be set to r2 <r1, r0 with respect to the rotation radii r0, r1 shown in FIGS. 6 and 8 depending on the inclination of the stage and the shape of the holding jig 8.
[0059]
It can be easily understood that the present embodiment provides the same effects as those of the embodiment shown in FIGS. 1 to 4 described above.
[0060]
It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.
[0061]
【The invention's effect】
According to the present invention, the object to be inspected can be finely moved in a plane perpendicular to the rotation axis of the rotating base while the X-ray irradiation is continued, and the specific portion inside the object to be inspected is projected image thereof. Can be adjusted so as to be positioned near the rotation axis, so that the image of the reconstructed internal structure data can be prevented from deteriorating.
In addition, while the X-ray irradiation is continued, it is possible to adjust the position of the specific part inside the object to be inspected so that the projected image thereof is located at the center of the two-dimensional detecting means. The time required for the adjustment can be reduced in comparison.
[0062]
Further, according to the present invention, while the X-ray irradiation is continued, the object to be inspected is finely rotated around a turning center axis orthogonal to the rotation axis of the rotating base portion, so that a plurality of objects are provided inside the object to be inspected. Even when parts having high X-ray absorption coefficients are arranged on a straight line, the heights of these parts can be individually separated in the vertical direction to specify the part to be observed of the object to be inspected. The quality of the internal structure data to be obtained can be improved.
[0063]
Further, according to the present invention, when using an air bearing for the bearing of the rotating base, while rotating the rotating base and capturing a projected image, while separating the drive source of the fine movement means from the entire rotating mechanism, Immediately before disconnecting the drive source from the entire rotation mechanism of the rotating base, the coordinate position of the inspection object is held by the holding means, and during the coordinate position adjustment period of the inspection object, the holding operation by the holding means is released. As a result, external force in the radial direction with respect to the rotating shaft is discharged, and the concentricity of the rotating shaft of the rotating base can be maintained.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of an embodiment of an X-ray tomographic imaging apparatus according to the present invention, wherein A is a top view and B is a side view.
FIG. 2 is a configuration diagram of an X-ray tomographic imaging apparatus.
FIG. 3 is a schematic view of a main part of the X-ray tomographic imaging apparatus of the present invention as viewed from above.
FIG. 4 is a side view of FIG. 3;
FIG. 5 is a flowchart for explaining an X-ray tomographic imaging apparatus according to the present invention.
FIG. 6 is a diagram for describing the present invention.
FIG. 7 is a diagram for describing the present invention.
FIG. 8 is a diagram for explaining a conventional example.
[Explanation of symbols]
1 ... X-ray tube, 2 ... X-ray two-dimensional detector, 3 ... Rotating base, 3a ... Vertical fine movement mechanism, 4 ... Bearing, 7 ... ..Test object, 9 horizontal fine movement table, 13 motor, 17 clamp mechanism, 25 gonio stage

Claims (5)

A rotation axis orthogonal to a perpendicular that is placed between the X-ray source and the two-dimensional detection unit that captures a projection image of the inspection object and that is lowered from the X-ray focal point to the light receiving surface of the two-dimensional detection unit In the X-ray tomographic imaging apparatus having a rotating base portion having, and a vertical fine movement mechanism for adjusting the position of the rotating base portion in the vertical direction,
An X-ray tomographic imaging apparatus comprising: a first fine movement unit having a horizontal fine movement position adjustment mechanism for adjusting a position on a plane orthogonal to the rotation axis on the rotation base portion. A rotation axis orthogonal to a perpendicular that is placed between the X-ray source and the two-dimensional detection unit that captures a projection image of the inspection object and that is lowered from the X-ray focal point to the light receiving surface of the two-dimensional detection unit In the X-ray tomographic imaging apparatus having a rotating base portion having, and a vertical fine movement mechanism for adjusting the position of the rotating base portion in the vertical direction,
An X-ray tomographic imaging apparatus comprising: a second fine movement unit including a gonio stage having a rotation center axis orthogonal to the rotation axis. A rotation axis orthogonal to a perpendicular that is placed between the X-ray source and the two-dimensional detection unit that captures a projection image of the inspection object and that is lowered from the X-ray focal point to the light receiving surface of the two-dimensional detection unit In the X-ray tomographic imaging apparatus having a rotating base portion having, and a vertical fine movement mechanism for adjusting the position of the rotating base portion in the vertical direction,
A first fine movement unit having a horizontal fine movement position adjustment mechanism for performing position adjustment on a plane orthogonal to the rotation axis is provided on the rotation base portion,
An X-ray tomographic imaging apparatus, further comprising a second fine movement unit including a gonio stage having a rotation center axis orthogonal to the rotation axis. The X-ray tomographic imaging apparatus according to claim 1, 2 or 3,
An X-ray tomographic imaging apparatus, wherein a drive source of the first and second fine movement means is separated from the entire rotating base while capturing a projection image of the object to be inspected. The X-ray tomographic imaging apparatus according to claim 4,
Providing holding means for holding the inspection object coordinates,
Immediately before disconnecting the drive source from the entire rotating base unit, the holding unit holds the inspection object coordinates,
An X-ray tomographic imaging apparatus, wherein the holding operation of the inspection object coordinates by the holding means is canceled during the inspection object coordinate position adjustment period.

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